Geoid data and thermal structure of the oceanic lithosphere
Geoid data and thermal structure of the oceanic lithosphere
复制标题
海洋岩石圈的大地水准面数据和热结构
DOI：
10.1029/95gl01595
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发表时间：
1995
影响因子：
5.2
通讯作者：
M. Zuber
中科院分区：
文献类型：
--
作者：
W. Richardson;S. Stein;C. Stein;M. Zuber
一个长期存在的问题是，旧的海洋岩石圈是否继续冷却作为边界层的半空间或接近热平衡，作为一个有限厚度的板模拟。虽然后者是从海底深度和热流最直接的推论，但也有人提出了其他解释。我们调查这个问题，使用已发表的结果的衍生物的海洋大地水准面与年龄估计从大地水准面偏移跨断裂带。这些数据没有被广泛用于分析岩石圈的热演化，主要是因为它们与两种常用的热模型不一致：半空间或125公里厚的板块。然而，最近的研究发现，更薄（95公里）的板块模型更适合深度和热流数据。因此，我们编译出版的大地水准面斜率的结果，并发现这些数据，虽然分散，可以区分模型。大地水准面斜率随年龄而变化，而不是像冷却半空间预测的那样保持不变。该变化大于厚板的预测值，薄板更适合。因此，大地水准面数据应有助于改进岩石圈的热模型。
A long-standing question is whether old oceanic lithosphere continues cooling as the boundary layer of a halfspace or approaches thermal equilibrium, as modeled by a finite thickness plate. Although the latter is the most direct inference from seafloor depths and heat flow, other explanations have been proposed. We investigate this issue using published results for the derivative of the oceanic geoid with age estimated from geoid offsets across fracture zones. Such data have not been used extensively in analyses of the thermal evolution of the lithosphere, primarily because they are inconsistent with two commonly used thermal models: a halfspace or a 125-km-thick plate. Recent studies, however, find that depth and heat flow data are better fit by a thinner (95 km) plate model. We thus compile published geoid slope results, and find that these data, though scattered, can discriminate between the models. Geoid slope changes with age, rather than being constant as predicted for a cooling halfspace. This variation is greater than predicted for a thick plate and is better fit by a thin plate. Geoid data should thus be useful for improving thermal models of the lithosphere.